What is deceleration?

westcoast

AzB Silver Member
Silver Member
I watch most of Earl's commentary videos for the Billiard Network and he often mentions deceleration as a flaw in a player's shot but he doesn't really explain what it is. My interpretation is that it is when you don't smoothly follow through on your shot, but I'm not sure that is what he means.
 
I watch most of Earl's commentary videos for the Billiard Network and he often mentions deceleration as a flaw in a player's shot but he doesn't really explain what it is. My interpretation is that it is when you don't smoothly follow through on your shot, but I'm not sure that is what he means.
Slowing down thru impact vs. a smoothly accelerating action.
 
deceleration: your cue speed is slower and slower as time passes.

Because your cue comes to a stop at some point for every stroke, your cue always decelerates for every stroke. I wonder if you can actually make your cue decelerate before you hit the cue ball? I think you would have to pretend the cue ball was 3 inches closer than it actually was, then set up your bridge to try and hit that imaginary cue ball. Then when your cue hit the real cue ball, your cue would be decelerating.

Suppose your cue wasn't accelerating through the cue ball, rather your cue maintained a constant speed through the cue ball. Compare that to a cue that accelerated through the cue ball. What's the difference in the result? The difference is the speed in which the cue hits the ball. So is Earl merely saying that the player didn't hit the cue ball hard enough?

A cue ball has no idea whether the cue was accelerating when it struck the cue ball, or whether the cue was traveling at a constant speed when it struck the cue ball, or whether the cue was decelerating when it struck the cue ball. All the cue ball knows is that it got struck at a certain speed.
 
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deceleration: your cue speed is slower and slower as time passes.

Because your cue comes to a stop at some point for every stroke, your cue always decelerates for every stroke. I wonder if you can actually make your cue decelerate before you hit the cue ball? I think you would have to pretend the cue ball was 3 inches closer than it actually was, then set up your bridge to try and hit that imaginary cue ball. Then when your cue hit the real cue ball, your cue would be decelerating.

Suppose your cue wasn't accelerating through the cue ball, rather your cue maintained a constant speed through the cue ball. Compare that to a cue that accelerated through the cue ball. What's the difference in the result? The difference is the speed in which the cue hits the ball. So is Earl merely saying that the player didn't hit the cue ball hard enough?

A cue ball has no idea whether the cue was accelerating when it struck the cue ball, or whether the cue was traveling at a constant speed when it struck the cue ball, or whether the cue was decelerating when it struck the cue ball. All the cue ball knows is that it got struck at a certain speed.
I see beginner/bad players do it all the time. Usually caused by indecision and they slow their arm down coming into impact. Also, the difference in the way the cueball reacts to a slowing vs. accelerating hit is NIGHT-N-DAY. Yes, the cue decelerates on every shot but when that decel takes place makes a huge difference in how cb behaves.
 
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I see beginner/bad players do it all the time. Usually caused by indecision and they slow their arm down coming into impact. Also, the difference in the way the cueball reacts to a slowing vs. accelerating hit is NIGHT-N-DAY. Yes, the cue decelerates on every shot but when that decel takes place makes a huge difference in how cb behaves.
Is having a hitch in one's stroke a more extreme example of this?
 
Is having a hitch in one's stroke a more extreme example of this?
It would depend on where the hitch is. If it's on the back portion of his stroke, then there's a chance the shooter may accelerate afterwards.

Think of a boxer throwing a punch and actually slowing down as it's landing, or a rocket as it's reaching its max ascent before arcing back to earth.
 
deceleration: your cue speed is slower and slower as time passes.

Because your cue comes to a stop at some point for every stroke, your cue always decelerates for every stroke. I wonder if you can actually make your cue decelerate before you hit the cue ball? I think you would have to pretend the cue ball was 3 inches closer than it actually was, then set up your bridge to try and hit that imaginary cue ball. Then when your cue hit the real cue ball, your cue would be decelerating.

Suppose your cue wasn't accelerating through the cue ball, rather your cue maintained a constant speed through the cue ball. Compare that to a cue that accelerated through the cue ball. What's the difference in the result? The difference is the speed in which the cue hits the ball. So is Earl merely saying that the player didn't hit the cue ball hard enough?

A cue ball has no idea whether the cue was accelerating when it struck the cue ball, or whether the cue was traveling at a constant speed when it struck the cue ball, or whether the cue was decelerating when it struck the cue ball. All the cue ball knows is that it got struck at a certain speed.
It has more to with what your arm does when it decelerates. It tenses up during the stroke which may cause you also to grip the cue tighter mid-stroke. Both of those things affect where you hit the cue ball. The other major thing is that yes, it does affect how hard you hit the ball. You end up striking the cue ball with less speed than you intend. This becomes a compounding factor because you have to work harder to get more cue power than someone who has proper acceleration. The more effort you expend to generate speed, the less accurate your stroke.
 
I watch most of Earl's commentary videos for the Billiard Network and he often mentions deceleration as a flaw in a player's shot but he doesn't really explain what it is. My interpretation is that it is when you don't smoothly follow through on your shot, but I'm not sure that is what he means.
Deceleration (in the sense Earl means it) is any slowing of the cue velocity prior to the CB leaving the tip of the cue.

Deceleration is accompanied by increasing grip pressure, tightening of the forearm muscles, and possibly shifting weight on the feet--none of which is good for the stroke.
 
Deceleration (in the sense Earl means it) is any slowing of the cue velocity prior to the CB leaving the tip of the cue.
I assume you mean "prior to the tip hitting the CB" - it must slow down when that happens (before the CB leaves the tip).

pj <- so many nits to pick, so little time
chgo
 
I assume you mean "prior to the tip hitting the CB" - it must slow down when that happens (before the CB leaves the tip).
I definition is making sure the CB is already off the tip before the cue starts decelerating.
Since contact time is on the order of 1 millisecond, the distinction makes little difference.
But it is the mindset: do not start deceleration until the CB is off traveling on its own.
 
Earl is smart enough to understand physics on the pool table

I never knew he had such a good technical vocabulary until this commentaries.

His personality pieces are off the chain

Let's reach out to Earls social media. Through Billiard Network and start the AZ fan group for Billiard Network
 
I watch most of Earl's commentary videos for the Billiard Network and he often mentions deceleration as a flaw in a player's shot but he doesn't really explain what it is. My interpretation is that it is when you don't smoothly follow through on your shot, but I'm not sure that is what he means.
Decelerating is slowing down the cue just before hitting the CB. It is explained and demonstrated starting at the 3:46 point in this video:


Enjoy!
 
Slowing down thru impact vs. a smoothly accelerating action.
There are a few shots that come up in pool where a decelerating stroke is actually the only way to get the cue ball to stop where you need it to, on a shot that has an angle to it and that you wouldn’t think it possible to get the cue ball to stop that quick.

It’s usually a combination of bottom inside spin and a decelerating stroke on an angled cut shot that gets the cue ball to stop much sooner after it strikes the cushion than any other possible option. In my opinion it is one those magical pool shots that defies the laws of physics - Efren is amazing at this shot.
 
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There are a few shots that come up in pool where a decelerating stroke is actually the only way to get the cue ball to stop where you need it to,
Decelerating just lowers the speed of the cue just before contact - you can achieve the same thing by accelerating a little more gradually to that same lower speed without decelerating at the end. I think it's most consistent and controllable that way.

pj
chgo
 
Decelerating just lowers the speed of the cue just before contact - you can achieve the same thing by accelerating a little more gradually to that same lower speed without decelerating at the end. I think it's most consistent and controllable that way.

pj
chgo
Also, Efren is an alien. He does things that others either don't see or can't pull off.
 
Decelerating just lowers the speed of the cue just before contact - you can achieve the same thing by accelerating a little more gradually to that same lower speed without decelerating at the end. I think it's most consistent and controllable that way.
One other thing I think decelerating might do is "dip the tip", both slowing the tip down and adding a little downward angle as it strikes the CB for better draw action (which can also be duplicated without decelerating, simply by raising the butt).

pj
chgo
 
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